The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth.[anon. (n.d). Ocean Regions: Blue Water – Characteristics. Available: . Last accessed 15 May 2014.][Rizk, F. (n.d). MARINE ENVIRONMENT AND PRIMARY PRODUCTIVITY. Available: . Last accessed 15 May 2014.]
From the point of view of marine biology it forms a relatively stable and well-illuminated environment for marine life, from plankton up to large fish and , while physical oceanography sees it as where the oceanic system interacts with the coast.
Definition (marine biology), context, extra terminology
In
marine biology, the
neritic zone, also called
coastal waters, the
coastal ocean or the
sublittoral zone,
refers to the zone of the ocean where
sunlight reaches the
ocean floor, that is, where the water is never so deep as to take it out of the
photic zone.
It extends from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters (660 feet).
Above the neritic zone lie the intertidal zone (or eulittoral) and supralittoral zones; below it the continental slope begins, descending from the continental shelf to the abyssal plain and the pelagic zone.
Within the neritic, marine biologists also identify the following:
-
The infralittoral zone is the algal-dominated zone down to around five metres below the low water mark.
-
The circalittoral zone is the region beyond the infralittoral, which is dominated by sessile animals such as .
-
The subtidal zone is the region of the neritic zone which is below the intertidal zone, therefore never exposed to the atmosphere.
Physical characteristics
The neritic zone is covered with generally well-oxygenated water, receives plenty of sunlight, is relatively stable
temperature, has low water pressure and stable
salinity levels, making it highly suitable for
photosynthesis life.
There are several different areas or zones in the ocean. The area along the bottom of any body of water from the shore to the deepest abyss is called the
benthic zone. It is where decomposed organic debris (also known as ocean 'snow') has settled to form a sediment layer. All
photosynthesis life needs light to grow and how far out into the ocean light can still penetrate through the water column to the floor or
benthic zone is what defines the neritic zone. That
photic zone, or area where light can penetrate through the water column, is usually above ~100 meters (~328 feet). Some coastal areas have a long area of shallow water that extends far out beyond the landmass into the water and others, for example islands that have formed from ancient volcanos where the 'shelf' or edge of the land mass is very steep, have a very short neritic zone.
Life forms
The above characteristics make the neritic zone the location of the majority of sea life.
[ Office of Naval Research ]
The result is high primary production by photosynthetic life such as
phytoplankton and floating
sargassum;
zooplankton, free-floating creatures ranging from microscopic
foraminiferans to small fish and
shrimp, feed on the phytoplankton (and one another);
both
trophic levels in turn form the base of the
food chain (or, more properly,
food web) that supports most of the world's great
wild fisheries.
are also mostly found in the neritic zone, where they are more common than in the
intertidal zone as they have less change to deal with.
Definition (physical oceanography)
In physical oceanography, the
sublittoral zone refers to coastal regions with significant
tide flows and
energy dissipation, including
,
,
river outflows and
.
As in marine biology, this zone typically extends to the edge of the continental shelf.
See also
